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New Scientist Live

Robot surgeon can slice eyes finely enough to remove cataracts

The Axsis robot can manage the fine movements needed for cataract surgery. Its makers hope it will cut complications, and find uses in other parts of the body

Didn’t spill a drop of blood…

Axsis / Cambridge Consultants

By Sally Adee

IT’S a real eye-opener. A surgical robot can make the micro-scale movements needed for the delicate procedure of cataract surgery.

Axsis, a small teleoperated system developed by roboticist Chris Wagner and his colleagues at Cambridge Consultants, UK, is designed to cut into the eye with greater accuracy than a human.

Globally, 20 million people a year have surgery on cataracts. They develop when the lens of the eye gets cloudy. To restore sight, a surgeon cuts a small hole in the lens, scoops out the cloudy bit, and replaces it with a plastic lens.

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The process requires a steady hand, and a common complication arises if a surgeon accidentally pierces the back of the lens, causing hazy vision.

Axsis is designed to prevent such human errors. It has articulating pincers sticking out of “arms” about the size of drinks cans, with strong, light “tendons” made of the same material that NASA uses for its solar sails. A surgeon uses two joysticks to control the pincers while watching on a screen as they work. This is just a demonstration model (pictured); in the final product, the pincers will be replaced with scalpels.

“It won’t let you make the mistake of punching through the back of the lens“

One benefit of the system is that the software prevents certain boundaries being breached. “It won’t let you make the mistake of punching through the back of the lens,” says Wagner.

Surgeons already use robots, such as the da Vinci system, for some operations. But these robots are usually large, often completely enveloping the patient and using long, telescoping instruments. Axsis is scaled down to a small halo around the patient’s head.

And while other robots work at small scales – even on eyes – they haven’t done cataract surgery. Trials of a system developed by Dutch medical robotics firm Preceyes are ongoing at Oxford’s John Radcliffe Hospital and focus on the retina, rather than the lens.

Ophthalmologist Ian Murdoch at University College London says he is interested in the idea that Axsis prevents the back of the lens from being pierced. “This happens in about 0.1 to 0.7 per cent of cases,” he says. “If the complication rate is less then this would obviously be great.”

But Murdoch wonders whether Axsis provides much of an advantage over existing advanced cataract surgery techniques, such as laser cataract surgery.

Peter Kim, a surgeon at the Children’s National Health System in Washington DC, says microsurgical robots are already used in some clinical settings. “I applaud the miniaturisation, but I am not clear on the unmet need and value proposition,” he says.

Axsis’s creators say cataract surgery is just the start. “It will quickly find more applications,” says Wagner. It could, for example, be used in gastrointestinal operations. Put the pincer end of Axsis on an endoscope and it could solve minor problems – like removing polyps – then and there.